Windows Server 2016 failover cluster setup with Azure shared disk

Just a minor correction: you can attach disks from the portal (GUI) without a PowerShell. On the VM you wanted, click the "disk" tab and it will give you two options (to create a new one or attach an existing shared disk)..so you can choose the "attach" option. But first, you have to make sure that the host-caching is disabled or none, otherwise you will not be able to attach the shared disk because host-caching is not supported for shared disks.